Hi I need some help with how express handles routes.
In setting up my express app, I have something like this:
app.use(express.static('public'));
Next, I mount some api routes:
app.use('/api', myrouter);
app.get('*', function(req, res) {
res.sendFile(path.resolve('public/index.html'));
});
But, when the frontend requests data via an api route, e.g. at 'localhost:3000/api/things', I am seeing in the Express debug logs that at some point (unsure when) it actually tries to serve this request as a static file, like:
send stat "C:\myproject\public\api\things" +230ms
Even though this folder doesn't exist in 'public' and should be solely handled by my api. FYI, the handler for /api/things route is only implemented for the GET method, and does get invoked at some point.
How do I stop express server from also trying to serve api requests from the static folder?
Thanks very much.
Answering my own question... which appears to be a duplicate of this one:
`express.static()` keeps routing my files from the route
So the answer is this one: https://stackoverflow.com/a/28143812/8670745
In short, the app.use() declarations that mount your api routers should appear before the app.use() statements which tell express.static where to serve your static files from. This way, the latter acts as a catchall AFTER api route handling is done. Router engine order matters...
Your answer is misinformed, or rather you've misinterpreted the problem. Your original configuration:
app.use(express.static(__dirname + 'public'));
app.use('/api', myrouter);
Looks absolutely fine because there's no clash between the routes. The threads you've linked too aren't really the same, and I can see why moving the routes in those cases would have worked.
The only thing I'd say is your path to your static folder isn't reliable, you should really use path.join, or actually in your case you can just do express.static('public') - express will infer the folder your app is served from.
My folder hierarchy is as follows;
public
----index.html
src
----server.js
when I run the code
var express = require('express');
var app = express();
var serv = require('http').Server(app);
var net = require('net');
var path = require('path');
var port = 3000;
app.use('/../public/', express.static(path.join(__dirname + '/../public/')));
app.get('/', function(req,res){
res.sendFile(__dirname + '/../public/index.html');
});
serv.listen(3000, function(){
console.log('port ' + port + ' is started to being listened')
});
var io = require('socket.io')(serv,{});
it returns forbidden error. How can I reach a file in another subfile?
First of all, what I thought solved it actually didn't solve because I am running multiple projects to understand the basics and I was confused. But now everything is clear. What I am actually trying to do is trying to use express to divide everything to folders. As I didn't know much about http, I watched a lot of videos and finally, I figured it out after watching official introduction video of express on youtube.
Here again what I am trying to accomplish;
-localhost
--public
---index.html
--src
---all server js files and other files that will concern game programming.
As I was trying to reach above, I couldn't manage to do it. What did actually do the trick is;
creating a variable that specifies 'public' directory which is another sub directory under localhost and use it as static which was simple from the beginning but as I didn't know much, I wasn't able to use it after studying few tutorials. As Michael mentioned above, I didn't even need following lines;
app.get(publicDir, function(req, res){
res.sendFile('index.html');
})
All I did was;
var publicDir = require('path').join(__dirname, '/../public');
app.use(express.static(publicDir));
app.use('/../public/'
doesn't really make sense. This parameter is representing the request URL. You can't listen for request URL's which are in the hierarchy somewhere else but not inside your root folder.
Remember that app.use('/' equals a request URL like http://localhost:3000 - meaning this is the absolute basis of the website - the so called root. So where should '/../public' point to? There is no URL with which you could reach such an address.
If you write app.use('/public' it will listen for requests on http://localhost:3000/public
But of course you can send files located in a file structure like you have. So probably what you wanted is:
app.use(express.static(__dirname + '/../public'));
in order to search the static files in a folder structure like:
public
-styles.css
-script.js
-index.html
server
-currentscript.js
where you could access static files like http://localhost:3000/styles.css
You can also completely remove this controller:
app.get('/', function(req,res){
res.sendFile(__dirname + '/../public/index.html');
});
static files like HTML are already served by the Express static files controller mentioned above.
This is enough to access your index.html by calling http://localhost:3000
This is the code that I see everywhere for a simple static web server using node.js and express:
var express = require('express');
var app = express();
app.use(express.static(__dirname + '/public'));
app.listen(8080);
My question is how does express know when the request is for a static page vs. a dynamic page? For example, why would /index.html be served from the public folder and not from dynamic templates?
Thanks.
You can think of the routes you define as a chain of checks on the path defined in the URL. Express iterates one by one through each check looking for a match; once it finds one, it executes that callback.
In this case, express.static is defining a bunch of path checks for each file in the public directory. If you app.use(express.static(__dirname + '/public')); before your app.get('/index.html', function(req, res) { ... code, and there is an index.html file in there, it will use the static file over the dynamic one.
That's basically it.
I'm trying to build a simple searching/browsing service for a server and I thought it could be interesting to use express for that to get familiar with it.
For the problem I'm considering, I have express#3.4.1 and a very simple app.js
var express = require("express");
var app = express();
//var express = require('express')
//, app = express.createServer();
app.configure(function() {
var hourMs = 1000*60*60;
app.use(express.static(__dirname + '/public', { maxAge: hourMs }));
app.use(express.directory(__dirname + '/public', {hidden: true, icons: true}));
app.use(express.errorHandler());
});
app.listen(1333);
How can I style/customize the HTML/CSS that the directory middleware produces ?
Should I overwrite express.directory.html in my app.js or is there a better/cleaner way ?
Edit : after looking at the code it seems overriding the function is not the way to go. the file it uses seems rather hard coded and I may end up copying the whole file to override what I want. So, any idea ?
You could extract all relevant code from the Express middleware, make your own adjustments, and save it as part of your app (as ./lib/middleware/directory.js or something).
If you're going to modify the files inside the node_modules/ directory you can be sure that you'll lose any modifications when you update.
You could rewrite express.directory.html(), but you might still run into the problem that any updates make it stop working because of internal changes.
I believe directly editing the node_modules/express/node_modules/connect/lib/public/style.css and directory.html would be the cleanest way of customizing the default express directory style/html.
Before I ask about app.router I think I should explain at least what I think happens when working with middleware. To use middleware, the function to use is app.use(). When the middleware is being executed, it will either call the next middleware by using next() or make it so no more middleware get called. That means that the order in which I place my middleware calls is important, because some middleware depends on other middleware, and some middleware near the end might not even be called.
Today I was working on my application and had my server running in the background. I wanted to make some changes and refresh my page and see the changes immediately. Specifically, I was making changes to my layout. I couldn't get it to work so I searched Stack Overflow for the answer and found this question. It says to make sure that express.static() is beneath require('stylus'). But when I was looking at that OP's code, I saw that he had his app.router call at the very end of his middleware calls, and I tried to figure out why that was.
When I made my Express.js application (version 3.0.0rc4), I used the command express app --sessions --css stylus and in my app.js file the code came setup with my app.router above both the express.static() and require('stylus') calls. So it seems like, if it comes already setup that way, then it should stay that way.
After re-arranging my code so I could see my Stylus changes, it looks like this:
app.configure(function(){
//app.set() calls
//app.use() calls
//...
app.use(app.router);
app.use(require('stylus').middleware(__dirname + '/public'));
app.use(express.static(__dirname + '/public', {maxAge: 31557600000}));
});
app.get('/', routes.index);
app.get('/test', function(req, res){
res.send('Test');
});
So I decided that the first step would be to find out why it is important to even have app.router in my code. So I commented it out, started my app and navigated to /. It displayed my index page just fine. Hmm, maybe it worked because I was exporting the routing from my routes file (routes.index). So next I navigated to /test and it displayed Test on the screen. Haha, OK, I have no idea what app.router does. Whether it is included in my code or not, my routing is fine. So I am definitely missing something.
So Here Is My Question:
Could somebody please explain what app.router does, the importance of it, and where I should place it in my middleware calls? It would also be nice if I got a brief explanation about express.static(). As far as I can tell, express.static() is a cache of my information, and if the application can't find the requested page, it will check the cache to see if it exists.
Note: This describes how Express worked in versions 2 and 3. See the end of this post for information about Express 4.
static simply serves files (static resources) from disk. You give it a path (sometimes called the mount point), and it serves the files in that folder.
For example, express.static('/var/www') would serve the files in that folder. So a request to your Node server for http://server/file.html would serve /var/www/file.html.
router is code that runs your routes. When you do app.get('/user', function(req, res) { ... });, it is the router that actually invokes the callback function to process the request.
The order that you pass things to app.use determines the order in which each middleware is given the opportunity to process a request. For example, if you have a file called test.html in your static folder and a route:
app.get('/test.html', function(req, res) {
res.send('Hello from route handler');
});
Which one gets sent to a client requesting http://server/test.html? Whichever middleware is given to use first.
If you do this:
app.use(express.static(__dirname + '/public'));
app.use(app.router);
Then the file on disk is served.
If you do it the other way,
app.use(app.router);
app.use(express.static(__dirname + '/public'));
Then the route handler gets the request, and "Hello from route handler" gets sent to the browser.
Usually, you want to put the router above the static middleware so that a accidentally-named file can't override one of your routes.
Note that if you don't explicitly use the router, it is implicitly added by Express at the point you define a route (which is why your routes still worked even though you commented out app.use(app.router)).
A commenter has brought up another point about the order of static and router that I hadn't addressed: the impact on your app's overall performance.
Another reason to use router above static is to optimize performance. If you put static first, then you'll hit the hard drive on every single request to see whether or not a file exists. In a quick test, I found that this overhead amounted to ~1ms on an unloaded server. (That number is much likely to be higher under load, where requests will compete for disk access.)
With router first, a request matching a route never has to hit the disk, saving precious milliseconds.
Of course, there are ways to mitigate static's overhead.
The best option is to put all of your static resources under a specific folder. (IE /static) You can then mount static to that path so that it only runs when the path starts with /static:
app.use('/static', express.static(__dirname + '/static'));
In this situation, you'd put this above router. This avoids processing other middleware/the router if a file is present, but to be honest, I doubt you'll gain that much.
You could also use staticCache, which caches static resources in-memory so that you don't have to hit the disk for commonly requested files. (Warning: staticCache will apparently be removed in the future.)
However, I don't think staticCache caches negative answers (when a file does not exist), so it doesn't help if you've put staticCache above router without mounting it to a path.
As with all questions about performance, measure and benchmark your real-world app (under load) to see where the bottlenecks really are.
Express 4
Express 4.0 removes app.router. All middleware (app.use) and routes (app.get et al) are now processed in precisely the order in which they are added.
In other words:
All routing methods will be added in the order in which they appear. You should not do app.use(app.router). This eliminates the most common issue with Express.
In other words, mixing app.use() and app[VERB]() will work exactly in the order in which they are called.
app.get('/', home);
app.use('/public', require('st')(process.cwd()));
app.get('/users', users.list);
app.post('/users', users.create);
Read more about changes in Express 4.
Routing means determining how an application responds to a client request to a particular endpoint, which is a URI (or path) and a specific HTTP request method (GET, POST, and so on).
Each route can have one or more handler functions, which are executed when the route is matched.
In Express 4.0 Router, we are given more flexibility than ever before in defining our routes.
express.Router() is use multiple times to define groups of routes.
route used as middleware to process requests.
route used as middleware to validate parameters using ".param()".
app.route() used as a shortcut to the Router to define multiple requests on a route
when we are using app.route(), we are attaching our app with that router.
var express = require('express'); //used as middleware
var app = express(); //instance of express.
app.use(app.router);
app.use(express.static(__dirname + '/public')); //All Static like [css,js,images] files are coming from public folder
app.set('views',__dirname + '/views'); //To set Views
app.set('view engine', 'ejs'); //sets View-Engine as ejs
app.engine('html', require('ejs').renderFile); //actually rendering HTML files through EJS.
app.get('/', function (req, res) {
res.render('index');
})
app.get('/test', function (req, res) {
res.send('test')
})
In express Version 4 we can easily define routes in the following manner:
server.js:
const express = require('express');
const app = express();
const route = require('./route');
app.use('/route', route);
// here we pass in the imported route object
app.listen(3000, () => console.log('Example app listening on port 3000!'));
route.js:
const express = require('express');
const router = express.Router();
router.get('/specialRoute', function (req, res, next) {
// route is now http://localhost:3000/route/specialRoute
});
router.get('/', function (req, res, next) {
// route is now http://localhost:3000/route
});
module.exports = router;
In server.js we imported the router object of the route.js file and apply it in the following manner in server.js:
app.use('/route', route);
Now all of the routes in the route.js have the following base URL:
http://localhost:3000/route
Why this approach:
The main advantage of taking this approach is that now our app is more modular. All the route handlers for a certain route now can be put into different files which makes everything more maintainable and easier to find.
An article by #kelyvinn from 2016, with the intent to demonstrate modularity, includes this code:
// controllers/apis/dogs/index.js
const
express = require('express'),
dogService = require('../../../services/dogs');
let router = express.Router();
router.get('/', dogService.getDogs);
router.get('/:id', dogService.getDogWithId);
module.exports = router;